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Prime Gold

Helpful Hints

https://sites.google.com/perryschools.org/mathpentathlon

Notes: I use slides 1-6 to teach and I print out slide 3 & 6 (front and back) for the students to use while learning the games.

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List of Prime Number up to 121

30 total prime numbers on the board (20 of them are “good” and 10 are “junk” Junk prime numbers are indicated with a . for example 2.) They are considered ‘junk’ prime numbers because they cannot be used to form a vein.

2.	3	5	7	11.	13
17	19	23	29	31	37
41	43	47	53	59.	61.
67.	71	73	79	83.	89.
97.	101.	103.	107	109	113

https://sites.google.com/perryschools.org/mathpentathlon

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101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

=

Good Prime

(20)

=

Junk Prime

(10)

https://sites.google.com/perryschools.org/mathpentathlon

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Divisibility Rules A number is Divisible by…

if the last digit is even or zero

Ex: any number ending in 0, 2, 4, 6, 8.

if the sum of the digits is divisible by

three

Ex: 105 (1+0+5=6) 6 is divisible by 3 so

105 is also divisible by 3.

if the last two digits are divisible by

four

Ex: 116 (16÷4=4) this rule is nearly

useless.

if the last digit is zero or five.

Ex: 5, 10, 15, 20, 25…

if the number is divisible by both two

and three. (OR even and divisible by 3)

Ex: 54 (5+4=9) 9 is divisible by 3 and 54 is

even.

if the last three digits are divisible by

eight.

Ex: 1888 (888÷8=111) this rule is useless.

if the sum of the digits is divisible by

nine.

Ex: 81 (8+1=9÷9) 9 is divisible by 9 so 81

is also divisible by 9.

if the last digit is zero.

Ex: 10, 20, 30, 40, 50…

2

3

4

5

6

8

9

10

https://sites.google.com/perryschools.org/mathpentathlon

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Factorials

1! = 1 = 1

2! = 2x1 = 2

3! = 3x2x1 = 6

4! = 4x3x2x1 = 24

5! = 5x4x3x2x1 = 120

6! = 6x5x4x3x2x1 = 720

7! = 7x6x5x4x3x2x1 = 5,040

https://sites.google.com/perryschools.org/mathpentathlon

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List of Prime Number up to 121

Prime Gold: Helpful Hints

30 total prime numbers on the board (20 of them are “good” and 10 are “junk” Junk prime numbers are indicated with a . for example 2.) They are considered ‘junk’ prime numbers because they cannot be used to form a vein.

Factorials

1! = 1 = 1

1! = 2x1 = 2

3! = 3x2x1 = 6

4! = 4x3x2x1 = 24

5! = 5x4x3x2x1 = 120

6! = 6x5x4x3x2x1 = 720

7! = 7x6x5x4x3x2x1 = 5,040

2.	3	5	7	11.	13
17	19	23	29	31	37
41	43	47	53	59.	61.
67.	71	73	79	83.	89.
97.	101.	103.	107	109	113

Divisibility Rules A number is Divisible by…

2 if the last digit is even or zero

Ex: any number ending in 0, 2, 4, 6, 8.

3 if the sum of the digits is divisible by three

Ex: 105 (1+0+5=6) 6 is divisible by 3 so 105 is also divisible by 3.

4 if the last two digits are divisible by four

Ex: 116 (16÷4=4) this rule is nearly useless.

5 If the last digit is zero or five.

Ex: 5, 10, 15, 20, 25…

6 if the number is divisible by both two and three. (OR even and

divisible by 3)

Ex: 54 (5+4=9) 9 is divisible by 3 and 54 is even

8 if the last three digits are divisible by eight.

Ex: 1888 (888÷8=111) this rule is useless.

9 if the sum of the digits is divisible by nine.

Ex: 81 (8+1=9÷9) 9 is divisible by 9 so 81 is also divisible by 9

10 if the last digit is zero.

Ex: 10, 20, 30, 40, 50…

https://sites.google.com/perryschools.org/mathpentathlon

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101.	100	99	98	97.	96	95	94	93	92	91
102	65	64	63	62	61.	60	59.	58	57	90
103.	66	37	36	35	34	33	32	31	56	89.
104	67.	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2.	11.	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83.
110	73.	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

## =

Good Prime

(20)

## =

Composite

##. =

Junk Prime

(10)

https://sites.google.com/perryschools.org/mathpentathlon

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101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

https://sites.google.com/perryschools.org/mathpentathlon

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121

101	100	99	98	97	96	95	94	93	92	91
102	65	64	63	62	61	60	59	58	57	90
103	66	37	36	35	34	33	32	31	56	89
104	67	38	17	16	15	14	13	30	55	88
105	68	39	18	5	4	3	12	29	54	87
106	69	40	19	6	1	2	11	28	53	86
107	70	41	20	7	8	9	10	27	52	85
108	71	42	21	22	23	24	25	26	51	84
109	72	43	44	45	46	47	48	49	50	83
110	73	74	75	76	77	78	79	80	81	82
111	112	113	114	115	116	117	118	119	120	121